Cytoskeleton

Question 1

Microtubules provide the backbone to?

Answer 1

Cilia and flagella

Question 2

Microtubules have what role in mitosis?

Answer 2

Make up mitotic spindle

Question 3

Microtubule size and composition

Answer 3

24nm hollow tube made of 13 protofilaments made of alpha-beta tubulin dimers

Question 4

Microtubule motor proteins

Answer 4

MAPs - kinesin (towards positive) dynein (towards negative)

Question 5

Catastrophe/Rescue

Answer 5

MT depolymerization is catastrophe, vs polymerization is rescue, both occur at the + end and are GTP-dependent active subunits

Question 6

MTOC

Answer 6

MT organizing center, centrosome, near the nucleus, MTs are nucleated there with the help of gamma tubulin

Question 7

MAPs

Answer 7

can be motor or non-motor proteins (stablization) for MTs

Question 8

Nucleation of MTs

Answer 8

only at centrosome with gamma-tubulin, vs polymerization can occur anywhere

Question 9

Basal body

Answer 9

MTOC equivalent of cilia and flagella

Question 10

Cilia/flagella structure and motility

Answer 10

the axoneme 9+2 MT structure, movement driven by dynein

Question 11

Disease associated with MT mutations

Answer 11

Immotile cilia syndrome, Kartagener’s syndrome, cancer - target of therapeutics

Question 12

Microfilaments structure

Answer 12

Non-hollow polymers of globulin protein actin, 7nm in diameter, NO organization center, barbed end (+) pointed end (-)

Question 13

Motor proteins of Microfilaments

Answer 13

Myosin, move towards positive end almost always, F-actin associated force, myosin II thick filament - polymer of myosin

Question 14

Microfilaments have what role in mitosis?

Answer 14

Cleavage furrow for pinching off in final stages of mitosis

Question 15

3 actin isoforms

Answer 15

alpha (muscle specific) beta gamma (more universal)

Question 16

MF polymerization is dept on what?

Answer 16

ATP

Question 17

Arp2/3

Answer 17

Branched MFs

Question 18

Formins/Spire

Answer 18

Bundled linear MFs

Question 19

Microvilli

Answer 19

Actin based epithelial projections - MFs

Question 20

How does the cytoskeleton attached to ECM

Answer 20

MFs

Question 21

Diseases associated with MFs

Answer 21

Hereditary spherocytosis, hereditary elliptocytosis, breast cancer

Question 22

Structure IFs

Answer 22

Non-polarized, 10nm in diameter, comparatively non-dynamic, gives tensile strength, specialized function depending on cell type, important for cell junctions, IF made of 8 strands

Question 23

Disease associated with IFs

Answer 23

Epidermolysis bullosa simplex, progeria